<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        header,footer{
            width:1000px;
            height:50px;
            background-color:orange;
            text-align: center;
            line-height: 50px;
            margin-left: 230px;
        }
        #one,#two,#three{
            width:1000px;
            height:400px;
            background-color: beige;
            text-align: center;
            line-height: 300px;
            border:1px,solid,black;
            margin-left: 230px;
        }
        .news{
            float:left;
            width:400px;
            height:400px;
            background-color:aquamarine;
            text-align: center;
        }
        .picture{
            float:right;
            width:400px;
            height:400px;
            background-color: darksalmon;
            margin-right: 200px;
            text-align: center;
        }
        #adv{
            position:fixed;
            background-color: pink;
            width:150px;
            height:200px;
            right:20px;
            top:300px;
            text-align: center;
            line-height: 200px;
        }

    </style>
</head>
<body>
    <header>百度一下</header>
    <main>
        <section id="one">
            <div class="news">新闻栏</div>
            <div class="picture">新闻图片</div>
        </section>

        <section id="two"> 
            <div class="news">新闻栏</div>
            <div class="picture">新闻图片</div>
        </section>

        <section id="three"> 
            <div class="news">新闻栏</div>
            <div class="picture">新闻图片</div>
        </section>

        <section id="adv">
            <div>广告</div>
        </section>


    </main>
    <footer>页脚</footer>
</body>
</html>